/* Gwenview: an image viewer Copyright 2000-2004 Aurélien Gâteau Copyright 2022 Ilya Pominov This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include "imageutils.h" #include namespace Gwenview { namespace ImageUtils { inline int changeBrightness(int value, int brightness) { return qBound(0, value + brightness * 255 / 100, 255); } inline int changeContrast(int value, int contrast) { return qBound(0, ((value - 127) * contrast / 100) + 127, 255); } inline int changeGamma(int value, int gamma) { return qBound(0, int(pow(value / 255.0, 100.0 / gamma) * 255), 255); } inline int changeUsingTable(int value, const int table[]) { return table[value]; } /* Applies either brightness, contrast or gamma conversion on the image. If the image is not truecolor, the color table is changed. If it is truecolor, every pixel has to be changed. In order to make it as fast as possible, alpha value is converted only if necessary. Additionally, since color components (red/green/blue/alpha) can have only 256 values but images usually have many pixels, a conversion table is first created for every color component value, and pixels are converted using this table. */ template static QImage changeImage(const QImage &image, int value) { QImage im = image; im.detach(); if (im.colorCount() == 0) { /* truecolor */ if (im.depth() != 32) { /* just in case */ // im = im.convertDepth( 32 ); in old version im.convertTo(im.hasAlphaChannel() ? QImage::Format_ARGB32 : QImage::Format_RGB32); } int table[256]; for (int i = 0; i < 256; ++i) { table[i] = operation(i, value); } if (im.hasAlphaChannel()) { for (int y = 0; y < im.height(); ++y) { QRgb *line = reinterpret_cast(im.scanLine(y)); for (int x = 0; x < im.width(); ++x) { line[x] = qRgba(changeUsingTable(qRed(line[x]), table), changeUsingTable(qGreen(line[x]), table), changeUsingTable(qBlue(line[x]), table), changeUsingTable(qAlpha(line[x]), table)); } } } else { for (int y = 0; y < im.height(); ++y) { QRgb *line = reinterpret_cast(im.scanLine(y)); for (int x = 0; x < im.width(); ++x) { line[x] = qRgb(changeUsingTable(qRed(line[x]), table), changeUsingTable(qGreen(line[x]), table), changeUsingTable(qBlue(line[x]), table)); } } } } else { auto colors = im.colorTable(); for (int i = 0; i < im.colorCount(); ++i) { colors[i] = qRgb(operation(qRed(colors[i]), value), operation(qGreen(colors[i]), value), operation(qBlue(colors[i]), value)); } } return im; } // brightness is multiplied by 100 in order to avoid floating point numbers QImage changeBrightness(const QImage &image, int brightness) { if (brightness == 0) { // no change return image; } return changeImage(image, brightness); } // contrast is multiplied by 100 in order to avoid floating point numbers QImage changeContrast(const QImage &image, int contrast) { if (contrast == 100) { // no change return image; } return changeImage(image, contrast); } // gamma is multiplied by 100 in order to avoid floating point numbers QImage changeGamma(const QImage &image, int gamma) { if (gamma == 100) { // no change return image; } return changeImage(image, gamma); } } // Namespace } // Namespace